The present invention relates to a method for processing display of computer, and in particular to a method of remote displaying and processing based on Server/Client architecture.
Normally, the known remote display control technique adopts Server/Client architecture. The Server is mainly used for acquiring image signal, analyzing, compressing and transmitting the variation of the image signal. For the display control mainly relates to the computer image on the internet, lossless compression is normally used, and considering the bandwidth limit of internet, the main object is to improve the compression ratio. The known lossless compression mainly comprises the following types: run length encoding (RLE), huffman coding compression, dictionary compression, arithmetic compression, MPEG compression (lossy or lossless compression is available). The principle of run length encoding is that: adjacent pixels with the same color value in a row are replaced by an enumerated data and the color value. For example, aaabccccccddeee may be represented by 3a1b6c2d3e. If an image consists of a plurality of large area with the same color, the compression ratio of this method would be surprising. However, this method has a vital defect that if every two adjacent points have different color, data amount would become double instead. Huffman coding is usual compression coding method, the principle of which is that the frequently appearing data is replaced by shorter code, while the less appearing data is replaced by longer code, and each data is of different code length. The defect of huffman coding is that it is necessary to scan the original image data twice, construct a binary tree and traverse the binary tree to generate coding, thus the speed of data compression and recovery is relative low. The dictionary compression is similar to the haffman coding, and the principle is that repeated character strings in the original data are used to construct a character table, and then an index value of the repeated character string in the character table is used to replace the original data so as to achieve compression. The dictionary compression is of high coding efficiency, but low speed in decoding. The arithmetic compression is also similar to the haffman compression, the frequently appearing data in the image data is replaced by shorter coding, while the less appearing data is replaced by longer code, so as to achieve data compression. Meanwhile, the arithmetic compression adopts the concept of dictionary compression, which compresses the data value and the value list, this method could obtain a higher compression ratio, but the arithmetic is so complex that the speed of compression and the speed of decompression are greatly affected. MPEG compression is also a method designed to improve the data transmission in the environment of narrow bandwidth, the method includes the types of intraframe compression and interframe compression, the intraframe compression is based on DCT coding technique, while the interframe compression adopts the techniques including forecasting method, difference compensation method, motion compensation method and so on. The MPEG arithmetic is relative complex and very effective to transmission in narrow bandwidth, but occupies high CPU resource and consumes the system resources seriously.
With the great improvement of transmission bandwidth, especially the transmission speed in LAN has reached the level of Giga Byte, it is unnecessary to pay more attention to compression ratio, and under such a condition, a new way for remote control displaying and processing which allows the remote control display window to display at nearly a real-time speed.